Rotary drilling tool



Jan 3, i925. 1,522,593

R. o. PICKIN ROTARY DRILLING TOOL Original Filed 061;. 1 1919 Patented.an. 13, 1925.

UNITED STATES PATENT OFFICE.

ROTARY DRILLING TOOL.

Application filed October 13, 1919, Serial No. 330,259. Renewed April12, 1924.

To all 107mm, iii-may concern:

Be it known that. I, ROWLAND O. PICKIN, a subject of the King of GreatBritain, residing in Los Angeles, in the county of Los Angeles and Stateof California, have invented a new and useful Improvement in RotaryDrilling Tools, of which the following is a specification.

This invention relates in general to improvements in rotary drillingtools and has more particular reference to rotary drill bits adapted foruse in drilling holes in rock strata of varying hardness.

The principal object of the invention is the provision of a rotary drillbit of new and improved construction and adapted to operate efficientlyand economically in the cutting of earth and rock strata, having widerange of hardness, i. e. adapted to cut effectively in strata varyingfrom very soft to very hard.

A further and highly important object of the invention is the provisionof a bit operable at great efliciency with a scraping QC tion, and yetso constructed that the parts wearing may be readily replaced.

A further and important object of the invention is the provision of arotary drill bit which acts by a scraping action on the side of thehole, and which will be so constructed and arranged that it will requirea relatively small amount of abrasive or cutting material.

Another object of the invention is the provision of a bit of thischaracter which may be cheaply manufactured, readily installed andeasily operated with any of the usual appropriate drilling apparatus.

Numerous other objects and advantages of the invention will be apparentas it is better understood from the following description, which takenin connection with the accompanying drawing discloses a preferredcmhodiment thereof.

Referring to the drawing:

Figure 1 is a side elevation of a drill bit embodying my presentinvention.

Figure 2 is a similar view taken at right angles to the view in Figure1.

Figure 3 is a section taken substantially on the line 33 of Figure 1.

Figure 4 is a plan view of one of the cutting studs.

Figure 5 is a transverse section through the same.

Figure 6 is a plan view of one of the abrasive cutting elements, and

Figure 7 is a longitudinal section through the same.

For the purpose of illustrating my invention I have shown on the drawinga drill bit in which it is embodied and adapted for attachment to adrill rod of any useful or preferred construction. The bit comprises abody or head 11 preferably of one piece and flattened at its sides, asindicated at 12. The remaining faces are preferably formed oftransversely curved sides 13 which extend down and around into asimilarly formed bottom face 14. In the embodiment of the inventionshown on the drawing the side and bottom faces 13 and 14; are the facescarrying the cutting elements, and these faces extend throughout thezone of cutting operation. In the embodiment of the invention shown onthe drawing two series of outwardly projecting studs 15 are provided.The studs of each series extending lengthwise of the faces and the studsof the two series being staggered with relation to each other andover-lapping, so that when the, drill is rotated continuous cutting atall points is accomplished. The cutting is done by grinding action andthe studs carry abrasive elements which cut into the bottom of the hole,and in so far as may be necessary into the sides of the hole, the sideaction being of course largely a smoothing and finishing one.

As has been stated the faces'13 and 14 are curved transversely and thecutting elements are or may be arranged on opposite sides of a verticaltransverse center.

In the present instance each cutting element comprises a carrier member16 having an operative end of a honeycomb construc tion, 1'. e. that isto say it is perforated so that much of the material is removed. Largerperforations 17 are provided in which abrasive sticks 18 are insertedand each of these sticks is preferably of cylin drical form and issurrounded by a cushioning sleeve 19 of copper or other soft andrelatively yielding material. The abrasive material of the sticks 18 maybe carborundum, extremely hard steel or the like and these cuttingelements are made hollow, as indicated at 20, to provide additionalcutting surface edge and to reduce the amount of material necessary.Additional holes 21 are provided in the carrier to reduce the amount ofmaterial in the operative end of the stud so that as the abrasiveelements wear down the relatively softer material of the carrier maymore easily be Worn away. The shank of the carrier is provided with anopening 16 in the present instance .for securing it in place and thematerial is further slit, as indicated at 22; Openings or apertures -23extend into the head at the proper locations and receive the shanks 16of the studs. The openings 16 are brought in registration with openings24 in the sides of the head so that bolts 25 in threaded engagement withthe stud shanks may be inserted; inner recesses 26 being provided totake the ends 27 of the bolts.

It will be manifest that various changes may be made in the form of thehead, in the cutting elements themselves and in their arrangement on thehead and that a less number of them may be'used, and also that they mayeven be combined with other cutting devices, all Without departing fromthe spirit and scope of the invention, the form of the inventionhereinbefore described being merely a preferred embodiment thereof andemployed solely for the purposes of illustration, it being understoodthat all structures that come Within the terms of the ap pended claimsare considered to also embody the invention.

I claim:

1. A rotary drill bit comprising a perforated head, carriers forcarrying groups of cutting elements and inserted in the head andindividually secured in place, and groups of cutting elements secured insaid carriers.

2. In a rotary drilling tool, a body, a plurality of rigid cutting studsinserted into said body, each having portions of its cutting faceperforated for the purpose of forming a plurality of cutting edges.

ROWLAND O. PICKIN.

